Simple Redis Operator

This is just a simplified example of a Kubernetes operator that deploys redis clusters. This is not to be used in a production environment.

This operator covers the following:

• Deploys a master redis instance with networking setup
• Deploys replicas redis instances that are setup to replicate the master instance
• Allows some basic settings of the redis instances
• Validation of input with sensible defaults

Potential roadmap items that could be added, but will not be for this iteration

• Setup state using a Storage Class
• Setup automated master election in case of failure of master redis instance
• Allow various scheduling options such as taints an tolerations
• TLS setup between replicas and master
• Allow for setting various other configurations on the redis instances
• Multi Master setup

Description

This is a simple redis operator, it will deploy a single master instance with as many replicas as specified.

This is not a production grade application but was rather used to show the different aspects of a Kubernetes operator including:

• Validating and Mutating Webhooks for sensible defaults as well as resource validation
• Reconcile logic
• Resource Ownership
• Idempotent Reonciliation

Getting Started

You’ll need a Kubernetes cluster to run against. You can use KIND to get a local cluster for testing, or run against a remote cluster. Note: Your controller will automatically use the current context in your kubeconfig file (i.e. whatever cluster kubectl cluster-info shows).

Running on the cluster

1. Install Instances of Custom Resources:

kubectl apply -f config/samples/

2. Build and push your image to the location specified by IMG:

make docker-build docker-push IMG=<some-registry>/simple-redis:tag

3. Deploy the controller to the cluster with the image specified by IMG:

make deploy IMG=<some-registry>/simple-redis:tag

Webhooks

Note: The webhooks setup will require you to setup TLS. Yopu will need to update the MutatingWebhookConfiguration and the ValidatingWebhookConfiguration and supply the Certs to the operator. You can read up more on how this works in the Deploying Admission Webhooks in the Kubebuilder Book

Uninstall CRDs

To delete the CRDs from the cluster:

make uninstall

Undeploy controller

UnDeploy the controller from the cluster:

make undeploy

Contributing

// TODO(user): Add detailed information on how you would like others to contribute to this project

How it works

This project aims to follow the Kubernetes Operator pattern.

It uses Controllers, which provide a reconcile function responsible for synchronizing resources until the desired state is reached on the cluster.

Test It Out

1. Install the CRDs into the cluster:

make install

2. Run your controller (this will run in the foreground, so switch to a new terminal if you want to leave it running):

make run

NOTE: You can also run this in one step by running: make install run

Modifying the API definitions

If you are editing the API definitions, generate the manifests such as CRs or CRDs using:

make manifests

NOTE: Run make --help for more information on all potential make targets

More information can be found via the Kubebuilder Documentation

License

Copyright 2023.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.